Megger SR-98, Instruction Manual

Page: 42 / 93

36
Knob, rotate the phase angle to the desired angle (note current lags voltage).
8.
Using the arrow key, highlight either
AC AMPERES
or
AC VOLTS
. Using the
Control Knob, decrease the AC Volts (or increase the AC Current) until the
TRIP
LED turns on. Read and record the
OHMS
value displayed.
Max
∠τ
(Angle of Torque) Test:
9.
Continue decreasing the AC Voltage (or increasing the AC Current) until well
inside the operating characteristic (TRIP LED stays ON).
10.
Using the arrow key, highlight the phase angle display. Using the Control Knob,
vary the Phase Angle clockwise until the contacts open and the LED turns OFF.
Note the Phase Angle (
θ
1).
11.
Vary the Phase Angle counter-clockwise. The LED will turn ON again
indicating that we are inside the operating characteristic. Continue moving in the
counter-clockwise direction until the LED turns OFF again. Note the Phase
Angle (
θ
2).
MAX
∠τ
= (
θ
1+
θ
2) / 2